Unlike motorcycles, there are no signal lights for bicycle
Since dangers occur all the time when bicycle is turning left or right in the middle of the crossroad, many countries are advising riders to send hand signs when take make turns.

It's because getting hands off the bicycle can cause risk on the traffic road
To prevent this, they are trying to get rid of the risk of hand signs by mounting signal lamps on the bicycle.

As commute with bicycle attracts many people, traffic road and environment for bicycle are showing improvement.
By mounting smartphone on the bicycle, riding distance could be measured and navigation is possible through GPS.
By mounting a battery inside the aluminum frame of the bicycle, it provides electricity to mounted smartphone and signal lamps.